In turbo-machines, such as in axial compressors, a working fluid flows through an inner volume. A part of the working fluid is bled off from the inner volume and is usually used for compressor management and for cooling or seal buffering purposes, e. g. in bearing areas. The bled off fluid may also be used to cool components in the turbine section of a gas turbine.
U.S. Pat. No. 4,155,680 discloses a compressor protection means. A compressor comprises a casing with a passage adapted to pass bleed air to a circumferentially extending bleed manifold surrounding the casing. Through apertures on a split line of adjacent vane platforms air is extracted into the circumferentially extending bleed manifold.
JP 2002 195196 A discloses a bleed structure of an axial compressor, wherein a casing of the compressor comprises the plurality of bleed holes for bleeding off an inner volume of the compressor.
U.S. Pat. No. 7,000,462 B discloses a compressor bleed air manifold for a blade clearance control. A compressor bleed air manifold includes annular outer flanges on opposite sides of a generally annular manifold plenum. Between two casing sections air from the compressor is bled off through a duct into the annular manifold plenum.
In many conventional systems for bleeding off air from an inner volume of a compressor, the air is injected directly into an annular main bleed chamber. Moreover, the channel between the main bleed chamber and the inner volume has to be casted into a vane carrier or a housing of the compressor. Alternatively, in a vane platform of a stator vane, holes are drilled for generating a fluid connection between the inner volume and the main bleed chamber.
EP 1 609 999 discloses a turbo-machine, wherein between a stator vane and a rotor blade air injection nozzles are formed at a stator housing. Air flows from an air chamber through the injection nozzle inside an inner volume of the turbo-machine.